Vehicle-exit assist apparatus

This is a National Stage of International Application No. PCT/JP2022/030803 filed Aug. 12, 2022, claiming priority based on Romanian Patent Application No. a 2021 00606 filed Sep. 30, 2021.

The present invention relates to a vehicle-exit assist apparatus capable of suppressing unnecessary operation of vehicle-exit assist control.

Hitherto, there has been known a vehicle-exit assist apparatus capable of executing vehicle-exit assist control for assisting an occupant of a vehicle in safely exiting a vehicle. The vehicle-exit assist apparatus is configured to execute the vehicle-exit assist control, for example, when a vehicle-exit intention of the occupant is detected in a case in which there is detected an interference target which may interfere with the safe vehicle-exit of the occupant (that is, may pass on a side of the vehicle) during the stop of the vehicle.

For example, a vehicle door control device described in Japanese Patent Application Laid-open No. 2007-138457 includes passing object detection means for detecting an object passing on the side of a vehicle, and is configured to notify, when an object passing on the side of the vehicle is detected by the passing object detection means in a case in which a slide door of the vehicle is in an open state, an occupant of existence of the object, and to suppress an operation of opening the slide door.

The vehicle-exit assist apparatus includes “a target information acquisition device for detecting a target existing on a rear side of the vehicle, and acquiring information on the detected target as target information,” and determines whether or not the detected target is an interference target based on the target information acquired by the target information acquisition device. The vehicle-exit assist apparatus typically determines whether or not the target is an interference target as described below.

That is, the vehicle-exit assist apparatus sets, as intersecting determination lines, virtual lines extending from left and right rear corner portions of the vehicle toward vehicle width outward directions (i.e., outward directions in a vehicle width direction), respectively, during the period in which the vehicle stops. After that, the vehicle-exit assist apparatus calculates a moving direction of the target based on the target information, and determines whether or not the target passes through the intersecting determination line within a predetermined period when the target continues to move along the moving direction. When the vehicle-exit assist apparatus determines that the target passes through the intersecting determination line within the predetermined period, the vehicle-exit assist apparatus determines that the target is an interference target.

Through the execution of the vehicle-exit assist control for the target determined as the interference target as described above, it is possible to reduce a possibility that the door or the occupant comes in contact with the interference target. Meanwhile, when this control is executed even in a scene in which the vehicle-exit assist control is not required, there is a possibility that the occupant is annoyed, and there is also a possibility that the safe vehicle-exit of the occupant is conversely interfered. Here, accuracy of the target information may decrease depending on detection precision of the target information acquisition device, resulting in an error in the calculation result of the moving direction of the target. As a result, even when the target does not actually intersect with the intersecting determination line after continuing to move along the current moving direction, there may be a case where the target is determined to be an interference target that passes through the intersecting determination line within the predetermined period. That is, “the scene in which the vehicle-exit assist control is not required” is such a scene that a target that does not actually corresponds to an interference target is erroneously detected as an interference target due to the occurrence of the error in the calculation result of the moving direction of the target. Thus, it is required to suppress the unnecessary operation of the vehicle-exit control, to thereby increase reliability of this control.

The present invention has been made in view of the above-mentioned problem. That is, one object of the present invention is to provide a vehicle-exit assist apparatus capable of suppressing unnecessary operation of vehicle-exit assist control.

According to at least one embodiment of the present invention (hereinafter “the present invention apparatus”), there is provided a vehicle-exit assist apparatus including: a target information acquisition device () configured to detect a target existing on a rear side of an own vehicle, and to acquire, as target information, information on the detected target; and a control unit () configured to execute vehicle-exit assist control of assisting an occupant of the own vehicle in safely exiting the own vehicle. The control unit () is configured to: determine, based on the target information, whether an interference target which is liable to interfere with the safe exit of the occupant from the own vehicle during a vehicle stop is detected; determine whether a vehicle-exit assist condition is satisfied, the vehicle-exit assist condition being satisfied at least when the interference target is detected; determine, when the vehicle-exit assist condition is satisfied, whether a specific condition is satisfied, the specific condition being satisfied when at least a part of the interference target exists in a rear-side vehicle width region (Rvw) being a region between a virtual line (L) extending from a left rear corner portion of the own vehicle toward a rear direction (−x-axis direction) in a front-and-rear direction (x-axis direction) of the own vehicle and a virtual line (L) extending from a right rear corner portion of the own vehicle toward the rear direction (−x-axis direction); execute the vehicle-exit assist control when the specific condition is not satisfied; and avoid executing the vehicle-exit assist control when the specific condition is satisfied.

The related-art vehicle-exit assist apparatus executes the vehicle-exit assist control, for example, when an execution condition, which is satisfied when the interference target is detected during the vehicle stop and the vehicle-exit intention of an occupant is detected, is satisfied. With this configuration, the vehicle-exit control is executed even when a target that does not actually correspond to an interference target is erroneously detected as an interference target due to an error in a calculation result of a moving direction of the target and the execution condition is consequently satisfied. Such execution of the vehicle-exit control thus causes unnecessary operation.

Here, the inventors of the present invention have found that when a target is erroneously detected as an interference target due to the occurrence of the error in the calculation result of the moving direction of the target, the target tends to be moving in a region extending on a directly rear side of the own vehicle. Based on this fining, when the vehicle-exit assist condition is satisfied, the present invention apparatus is configured not to immediately execute the vehicle-exit assist control, but to determine whether or not the specific condition, that is, the condition which is satisfied when at least a part of the interference target is positioned in the rear-side vehicle width region of the own vehicle, is satisfied. When the specific condition is not satisfied, the present invention apparatus is configured to determine that it is less liable that the target is erroneously detected as the interference target, and to execute the vehicle-exit assist control. When the specific condition is satisfied, the present invention apparatus is configured to determine that it is highly liable that the target is erroneously detected as the interference target due to the occurrence of the error in the calculation result of the moving direction of the target, and to avoid executing the vehicle-exit assist control.

With this configuration, the unnecessary operation of the vehicle-exit assist control can be suppressed while this control is appropriately executed in a scene in which this control is actually required, thereby being capable of increasing reliability of the vehicle-exit assist control.

According to at least one aspect of the present invention, of a front end portion of the interference target, a portion closest to the own vehicle in the vehicle width direction of the own vehicle is defined as a proximate portion (np), virtual lines that each have a predetermined length, are positioned on a reference axis (y-axis) passing through the left rear corner portion and the right rear corner portion of the own vehicle, and extend toward vehicle width outward directions from the left rear corner portion and the right rear corner portion, respectively, are defined as intersecting determination lines (LL, LR), and the control unit () is configured to: determine that the detected target is an interference target when an intersection between an extension line extending from the proximate portion (np) along a moving direction of the detected target and the reference axis (y-axis) is positioned on one of the intersecting determination lines (LL, LR), and a predicted period (TTC) predicted to be required for the detected target to reach the intersection is equal to or shorter than a predetermined period threshold value (TTCth); and determine that the specific condition is satisfied further when a magnitude (|Δy|) of a change amount per unit period of a position of the intersection is equal to or larger than a predetermined change amount threshold value (Δyth).

The inventors of the present invention have found that when a target is erroneously detected as an interference target due to the occurrence of the error in the calculation result of the moving direction, the magnitude of the change amount per unit period of the position of the intersection between the extension line extending from the proximate portion along the moving direction of the target and the reference axis tends to be relatively large. Based on this finding, the at least one aspect of the present invention is configured such that the specific condition is satisfied further when the magnitude of the change amount per unit period of the position of the intersection is equal to or larger than the change amount threshold value. With this configuration, the precision of the determination of whether or not the vehicle-exit control is the unnecessary operation becomes higher, and the vehicle-exit assist control can thus more appropriately be executed.

According to at least one aspect of the present invention, the control unit () is configured to determine that the specific condition is satisfied further when a component (vx) of a speed (v) of the interference target in the front-and-rear direction of the own vehicle is higher than 0 and is lower than a predetermined speed threshold value (vxth) and/or a component (dx) of a deceleration (d) of the interference target in the front-and-rear direction is equal to or higher than a predetermined deceleration threshold value (dxth).

The inventors of the present invention have found that when a target is erroneously detected as an interference target due to the occurrence of the error in the calculation result of the moving direction, the target tends to move at such a speed that “the component thereof in the front-and-rear direction of the own vehicle” has a relatively small value, and/or at such a deceleration that the component thereof in the front-and-rear direction has a relatively large value. Based on this finding, the at least one aspect of the present invention is configured such that the specific condition is satisfied further when the component of the speed of the interference target in the front-and-rear direction is higher than 0 and lower than the speed threshold value and/or the component of the deceleration of the interference target in the front-and-rear direction is equal to or higher than the deceleration threshold value. With this configuration, the precision of the determination of whether or not the vehicle-exit control is the unnecessary operation becomes still higher, and the vehicle-exit assist control can thus still more appropriately be executed.

In the description above, in order to facilitate understanding of the invention, reference symbols used in at least one embodiment of the present invention are enclosed in parentheses, and are assigned to each of constituent features of the invention corresponding to the at least one embodiment. However, each of the constituent features of the invention is not limited to the at least one embodiment prescribed by the reference symbols.

(Configuration)

Referring to the accompanying drawings, a vehicle-exit assist device (hereinafter also referred to as “present embodiment apparatus”) according to at least one embodiment of the present invention is described below. As illustrated in, the present embodiment apparatus includes a vehicle-exit assist ECU, and a vehicle speed sensor, a radar sensor, door opening/closing sensors, and a buzzer, which are connected to the vehicle-exit assist ECU. The vehicle-exit assist ECUincludes a microcomputer as a main component. The ECU is an abbreviation for “electronic control unit”. The microcomputer includes CPU, ROM, RAM, interface (I/F), and the like, and the CPU is configured to execute instructions (programs and routines) stored in the ROM to achieve various functions. A vehicle to which the present embodiment apparatus is mounted is referred to as “own vehicle”.

The vehicle-exit assist ECUis configured to acquire signals generated or output by the sensorstoeach time a predetermined period elapses, and to control the buzzerbased on the acquired signals. The vehicle-exit assist ECUis hereinafter simply also referred to as “ECU”.

The vehicle speed sensorgenerates a signal corresponding to a travel speed (hereinafter referred to as “vehicle speed”) of the own vehicle. The ECUacquires the signal generated by the vehicle speed sensor, and calculates the vehicle speed based on the signal. When the vehicle speed is zero, the ECUdetermines that the own vehicle is in a stop state (hereinafter also referred to as “during the vehicle stop”).

The radar sensor(target information acquisition device) has a function of acquiring information on a 3D object (target) existing on a rear side (on a directly rear side and obliquely rear sides) of the own vehicle. The 3D object is a moving object such as a vehicle, a bicycle, a pedestrian, and the like.

As illustrated in, the radar sensorincludes a left radar sensorL provided in a left rear corner portion of an own vehicle V and a right radar sensorR provided in a right rear corner portion of the own vehicle V. The radar sensorirradiates a radio wave in the millimeter waveband around the own vehicle. Specifically, the left radar sensorL irradiates the radio wave in a range including a left-side region RL on the left rear side of the own vehicle. The right radar sensorR irradiates the radio wave in a range including a right-side region RR on the right rear side of the own vehicle. Each of the left-side region RL and the right-side region RR has a shape extending outward and inward in a vehicle width direction as a position in the region becomes farther from the own vehicle V toward the rear side. In, for the sake of illustration, ratios of the regions RL and RR to the own vehicle V and the like are changed.

When a 3D object exists in the irradiation range of the radio wave, the radar sensorreceives a reflected wave from the 3D object. The radar sensorcalculates presence or absence of a 3D object and a relative relationship between the own vehicle and the 3D object (a distance from the own vehicle to the 3D object, an orientation of the 3D object with respect to the own vehicle, a relative speed of the 3D object with respect to the own vehicle, and the like) based on an irradiation timing, a reception timing of the radio wave, and the like. In other words, the radar sensordetects a 3D object existing on the rear side of the own vehicle. The 3D object detected by the radar sensor(that is, the 3D object existing in the region RL or RR) is hereinafter also referred to as “target.” The radar sensoroutputs, as target information, those pieces of information on the target to the ECU.

The sensor for acquiring the target information is not limited to the radar sensor. For example, in addition to or in place of the radar sensor, a laser radar sensor, an ultrasonic sensor, and/or a camera sensor, and so on may be used. As another example, as the radar sensor, a sensor to be used for blind spot monitor control may be used. The blind spot monitor control is control of attracting attention of a driver of the own vehicle when a vehicle approaching the own vehicle from the rear side (in particular, a vehicle existing in a region which is hard to be checked through side mirrors) is detected.

Description is to be continued with reference again to. The door opening/closing sensoris provided for each of a plurality of doors (in more detail, side doors) of the own vehicle. The door opening/closing sensordetects an open state and a closed state of the door. When the door opening/closing sensordetects that the door is in an open state, the door opening/closing sensorgenerates, during a period in which the open state is being detected, an open signal indicating that the door is in the open state. When the door opening/closing sensordetects that the door is in a closed state, the door opening/closing sensorgenerates, during a period in which the closed state is being detected, a closed signal indicating that the door is in the closed state. The ECUdetects which of the open signal and the closed signal each door opening/closing sensoris generating, and detects whether the door corresponding to the door opening/closing sensoris in the open state or the closed state based on the detection result.

The buzzeris built into a meter panel (not shown), and is configured to sound based on a drive command from the ECU.

(Details of Operation)

A related-art vehicle-exit assist apparatus is configured to execute the vehicle-exit assist control, for example, when a vehicle-exit intention of the occupant is detected in a case in which an interference target which is liable to interfere with the safe vehicle-exit of the occupant during the vehicle stop is detected. With this configuration, there is a possibility that a target that does not actually corresponds to an interference target is erroneously detected as an interference target due to an occurrence of an error in a calculation result of a moving direction of the target, and, as a result, unnecessary vehicle-exit assist control is executed.

Thus, the inventors of the present invention have configured the present embodiment apparatus as follows based on the finding that “the error in the calculation result of the moving direction of a target is liable to occur when the target is moving in a region extending on a directly rear side of the own vehicle”. That is, in the case in which the interference target is detected during the vehicle stop and the vehicle-exit intention of the occupant is detected, when there is satisfied a specific condition (described below) being “a condition which is liable to be satisfied when an interference target is moving in the region extending on the directly rear side of the own vehicle,” the present embodiment apparatus is configured to determine that the interference target does not actually correspond to an interference target, and to avoid executing the vehicle-exit assist control. In the at least one embodiment, the ECUexecutes warning control as the vehicle-exit assist control. The warning control is control of executing processing of sounding the buzzer. A detailed description is now given of operation of the ECU.

When all of the following condition 1 to condition 3 are satisfied, the ECUdetermines that a warning condition is satisfied. The warning condition corresponds to an example of “a vehicle-exit assist condition.”

First, description is given of the condition 1. When the vehicle speed acquired from the vehicle speed sensoris zero, the ECUdetermines that the condition 1 is satisfied.

Description is now given of the condition 2. The “interference target” means a moving object which is liable to approach the own vehicle from the rear side to interfere with the safe vehicle-exit of the occupant (that is, to pass on the side of the own vehicle). The ECUdetects the interference target as described below. That is, when the ECUdetermines that a target exists in the left-side region RL or the right-side region RR based on the target information acquired from the radar sensor, the ECUcalculates a predicted period that is predicted to be required for the target to come in contact with or to reach a position closest to the own vehicle. This predicted period is hereinafter also referred to as “time to collision (TTC)” for the convenience of description. When the TTC is equal to or shorter than a predetermined period threshold value TTCth, the ECUdetects this target as an interference target, and thus determines that the condition 2 is satisfied.

With reference to, a more detailed description is now given.shows a state in which another vehicle Vt is approaching the own vehicle V from the rear side. As illustrated in, when the own vehicle is in the stop state (that is, the condition 1 is satisfied), the ECUsets an xy coordinate system having an origin at a center between the left and right rear corner portions of the own vehicle V. The “x” axis extends in a front-and-rear direction of the own vehicle V. The “y” axis extends in the vehicle width direction (left and right direction) of the own vehicle V. That is, the “y” axis can be considered as an axis passing through the left and right rear corner portions of the vehicle V. In the at least one embodiment, the center of the left and right rear corner portions of the own vehicle V matches a center portion of a rear end of the own vehicle V. The “y” axis corresponds to an example of “a reference axis.”

Moreover, the ECUsets an intersecting determination line L to the own vehicle V when the own vehicle V is in the stop state. The intersecting determination line L is a virtual line set to calculate the TTC, and includes a left-side intersecting determination line LL and a right-side intersecting determination line LR. The left-side intersecting determination line LL extends from the left rear corner portion of the own vehicle V toward a −y-axis direction (toward the vehicle width outward direction) on the “y” axis. The right-side intersecting determination line LR extends from the right rear corner portion of the own vehicle V toward a +y-axis direction (toward the vehicle width outward direction) on the “y” axis. Lengths of the left and right intersecting determination lines LL and LR are the same as each other (for example, approximately 1.3 m), and are substantially equal to lengths of the regions RL and RR in the y-axis direction at the left and right rear corner portions of the own vehicle V. The lengths of the left and right intersecting determination lines LL and LR are set in advance through experiments or simulation to such a length that “when a target passes through any position on the determination line LL or LR during the vehicle-exit of the occupant from the own vehicle V, the target is liable to come in contact with the door or the occupant of the own vehicle V.”

The ECUcalculates a speed vector A of the target (the another vehicle Vt in the example of) based on the target information when the own vehicle V is in the stop state, and sets a start point of the speed vector A to a proximate portion np of the target. The proximate portion np is a portion of a front end portion of the target which is closest to the own vehicle V in the y-axis direction. The speed vector A may be, for example, obtained through time differentiation of the position (distance and orientation) of the target.

When an extension line of the speed vector A of the target intersects with any one of the left and right intersecting determination lines LL and LR (that is, an intersection between the extension line and the “y” axis is positioned on the intersecting determination line L), the ECUcalculates, as the TTC, “a period predicted to be required for the target to intersect with the intersecting determination line L (that is, a period predicted for the target to reach the intersection between the extension line of the speed vector A of the target and the intersecting determination line L).” The TTC may be calculated through use of the target information by dividing, for example, “a distance from the proximate portion np to the intersection” by “a current speed of the target.”

When the TTC in the case in which the target intersects with the left-side intersecting determination line LL in the future is equal to or lower than the TTCth, the ECUdetermines that the target is liable to interfere with a safe vehicle-exit of the occupant from the door on the left side, and thus detects the target as an interference target for the door on the left side.

Meanwhile, when the TTC in the case in which the target intersects with the right-side intersecting determination line LR in the future is equal to or lower than the TTCth, the ECUdetermines that the target is liable to interfere with a safe vehicle-exit of the occupant from the door on the right side, and thus detects the target as an interference target for the door on the right side.

In those cases, the ECUdetermines that the condition 2 is satisfied.

Meanwhile, when the target intersects with any one of the left and right intersecting determination lines LL and LR in the future, but the TTC is longer than the TTCth, the ECUdetermines that the target is not (currently) liable to interfere with the safe vehicle-exit of the occupant, and does not thus detect the target as an interference target.

In contrast, when the extension line of the speed vector A of the target intersects with none of the left and right intersecting determination lines LL and LR (that is, the intersection between the extension line and the “y” axis is not positioned on the intersecting determination line L), the TTC cannot be calculated, and the ECUdoes not thus detect the target as an interference target.

In those cases, the ECUdetermines that the condition 2 is not satisfied.

In the example of, the another vehicle Vt crosses the right-side intersecting determination line LR in the future in consideration of the speed vector A at the current time point. Thus, the ECUcalculates the TTC for the another vehicle Vt, detects the another vehicle Vt as an interference target for the door on the right side when the TTC is equal to or shorter than the TTCth, and does not detect the another vehicle Vt as an interference target when the TTC exceeds the TTCth.

Even when the extension line of the speed vector A of the target does not intersect with the intersecting determination line L, the ECUcalculates a “y” coordinate of the intersection with the “y” axis. Thus, when “y” coordinates of end points of the left and right intersecting determination lines LL and LR are denoted by −Ly and Ly, respectively, and the vehicle width of the own vehicle V is denoted by “w”, the state in which “the extension line of the speed vector A of the target intersects with any one of the left and right intersecting determination lines LL and LR” is equivalent to a state in which “the ‘y’ coordinate of the intersection between the extension line of the speed vector A of the target and the ‘y’ axis satisfies −Ly≤y≤−w/2 or w/2≤y≤Ly.”

Description is now given of the condition 3. When the ECUdetermines that the door on the side on which the interference target is detected is in the open state based on the signal acquired from the door opening/closing sensors, the ECUdetermines that the condition 3 is satisfied.

When the warning condition is satisfied, the ECUdetermines whether or not the specific condition is satisfied for an interference target satisfying the warning condition. In general, detection precision of the radar sensortends to decrease when a target that is moving in “the region extending on the directly rear side of the own vehicle” is to be detected. When the target is moving in this region, at least a part of the target is overlapping the own vehicle in the y-axis direction. Assuming that the target is moving straight in the x-axis direction, when the target partially overlaps the own vehicle as described above, it is less liable that the target passes on the side of the own vehicle in the future. That is, the target hardly becomes an interference target. Meanwhile, when the target changes a travel direction, and passes on the side of the own vehicle in the future (that is, becomes an interference target), it is considered to be sufficient that the warning control is executed at the time when the travel direction is changed (that is, at the time when the target no longer overlaps the own vehicle). From the above, the inventors of the present invention have set the specific condition through experiments and/or simulation based on the finding that when a target detected as an interference target is moving in the region extending on the directly rear side of the own vehicle, the target does not actually correspond to an interference target (that is, it is highly liable that the error occurs in the calculation result of the moving direction of the target due to the detection precision of the radar sensor, and the target is thus erroneously detected as the interference target). In the at least one embodiment, the ECUdetermines that the specific condition is satisfied when all of the following condition “a” to condition “c” are satisfied.

(Condition “a”) At least a part of an interference target is positioned in a rear-side vehicle width region Rvw of the own vehicle.

(Condition “b”) A magnitude |Δy| of a change amount per unit period of the “y” coordinate of the intersection between the extension line of the speed vector A of the interference target and the “y” axis is equal to or larger than a predetermined change amount threshold value Δyth.

(Condition “c”) An x-axis component vx of the speed of the interference target is higher than 0 and is lower than a predetermined speed threshold value vxth, and/or an x-axis component dx of the deceleration of the interference target is equal to or higher than a predetermined deceleration threshold value dxth.